1 . 用所给短语的恰当形式填入下列句子，使其意义完整，有两个短语多余。

apply for   be made up of   make a difference   work out graduate from   concentrate on   be addicted to

1. I often turn to Mr Li for help in order to ________ the difficult maths problems.
2. Li Feng is one of many examples of young people who are ________ in the world.
3. Unable to have enough sleep, he has much difficulty ________ the classes.
4. Since Joseph ________ college, he has been working on the development of an advanced AI program.
5. Hundreds of people ________ the job, but only three were accepted.